The discrete elicited lateral tongue movement first described under this project is the basis for psychophysical studies of oral sensation in the human newborn. This transverse reflex is elicited by touching the tongue or placing a drop of fluid on its dorsal surface. The reliable adaptation of this reflex with repeated elicitation has been incorporated into a demonstration of taste sensitivity. Adaptation to water stimuli leaves responding to sugar solutions unimpaired, but adaptation to sugar solutions suppresses responding to water drops. The newborn's sensitivity to both sweet and salty tastes are viewed in the context of the subsequent modification of these sensitivites with maturation and experience.